New collective modes in wide quantum wells with in-plane magnetic fields

We theoretically investigate, within the random phase approximation. the collective excitations of symmetric wide quantum Wells under in-plane magnetic fields B-parallel to. We find that the B-parallel to, field significantly affects the frequencies, (an-)isotropy and types of the ptasmon modes. In particular. a high B-\ can induce an additional branch of undamped acoustic-like plasmons, which does not exist in single quantum wells without B-parallel to. (C) 2002 Elsevier Science B.V. All rights reserved